Add power save documentation.

doc/html/Makefile.am

@@ -25,6 +25,7 @@ generated_html = \
 	overview.html \
 	platforms.html \
 	plugins.html \
+	power_save.html \
 	proctrack_plugins.html \
 	programmer_guide.html \
 	publications.html \

doc/html/Makefile.in

@@ -286,6 +286,7 @@ generated_html = \
 	overview.html \
 	platforms.html \
 	plugins.html \
+	power_save.html \
 	proctrack_plugins.html \
 	programmer_guide.html \
 	publications.html \

doc/html/documentation.shtml

@@ -22,6 +22,7 @@
 <li><a href="lci.7.tutorial.pdf">Resource Management Using SLURM, 
 (Tutorial, The 7th International Conference on Linux Clusters, May 2006)</li>
 <li><a href="big_sys.shtml">Large Cluster Administration Guide</a></li>
+<li><a href="power_save.shtml">Power Saving Guide</a></li>
 <li><a href="cons_res.shtml">Consumable Resources Guide</a></li>
 <li><a href="bluegene.shtml">Blue Gene User and Administrator Guide</a></li>
 <li><a href="ibm.shtml">IBM AIX User and Administrator Guide</a></li>
@@ -49,6 +50,6 @@ Jobs throuh LSF</a></li>
 <li><a href="mpiplugins.shtml">MPI Plugin Programmer Guide</a></li>
 </ul>
 
-<p style="text-align:center;">Last modified 24 April 2007</p>
+<p style="text-align:center;">Last modified 9 May 2007</p>
 
 <!--#include virtual="footer.txt"-->

doc/html/news.shtml

@@ -49,9 +49,11 @@ on a node.</li>
 provide vastly improved integration.</li>
 <li>BlueGene plugin permits use of different boot images per job 
 specification.</li>
-<li>Added event trigger mechanism with new tool <i>strigger</i>.</li>
+<li>Event trigger mechanism added with new tool <i>strigger</i>.</li>
 <li>Added support for task binding to CPUs or memory via <i>cpuset</i>
 mechanism.</li>
+<li>Added support for configurable 
+<a href="power_save.html">power savings</a> on idle nodes.</li>
 </ul>
 
 <h2><a name="13">Major Updates in SLURM Version 1.3 and beyond</a></h2>
@@ -69,6 +71,6 @@ and refresh.</li>
 </ul>
 
 
-<p style="text-align:center;">Last modified 1 May 2007</p>
+<p style="text-align:center;">Last modified 9 May 2007</p>
 
 <!--#include virtual="footer.txt"-->

doc/html/power_save.shtml

+<!--#include virtual="header.txt"-->
+
+<h1>Power Saving Guide</h1>
+<p>SLURM provides an integrated power saving mechanism beginning with 
+version 1.2.7.
+Nodes that remain idle for an configurable period of time can be placed 
+in a power saving mode. 
+The nodes will be restored to normal operation once work is assigned to them.
+Power saving is accomplished using a <i>cpufreq</i> governor that can change
+CPU frequency and voltage.
+Note that the <i>cpufreq</i> driver must be enabled in the Linux kernel 
+configuration. 
+While the "ondemand" governor can be configured to operate at all
+times to automatically alter the CPU performance based upon workload, 
+SLURM provides somewhat greater flexibility for power management on a
+cluster. 
+Of particular note, SLURM can alter the governors across the cluster
+at a configurable rate to prevent rapid changes in power demands. 
+For example, starting a 1000 node job on an idle cluster could result 
+in an instantaneous surge in power demand of multiple megawatts without 
+SLURM's support to increase power demands in a gradual fashion.</p>
+
+
+<h2>Configuration</h2>
+<p>Rather than changing SLURM's configuration file (and data 
+structures) after SLURM version 1.2 was released, we decided to 
+temporarily put the configuration parameters directly in the 
+<i>src/slurmctld/power_save.c</i> file.
+These paramters will all be moved into the <i>slurm.conf</i>
+configuration file when SLURM version 1.3 is released.
+Until that time, pleased directly edit the code to use this feature.
+The following configuration paramters are available:
+<ul>
+<li><b>IdleTime</b>:
+Nodes becomes elligible for power saving mode after being idle 
+for this number of seconds. 
+A negative number disables power saving mode.
+The default value is -1 (disabled).</li>
+<li><b>SuspendRate</b>:
+Maximum number of nodes to be placed into power saving mode 
+per minute. 
+A value of zero results in no limits being imposed.
+The default value is 60.
+Use this to prevent rapid drops in power requirements.</li>
+<li><b>ResumeRate</b>:
+Maximum number of nodes to be placed into power saving mode 
+per minute. 
+A value of zero results in no limits being imposed.
+The default value is 60.
+Use this to prevent rapid increasses in power requirements.</li>
+<li><b>SuspendProgram</b>:
+Program to be executed to place nodes into power saving mode.
+The program executes as <i>SlurmUser</i> (as configured in
+<i>slurm.conf</i>. 
+The argument to the program will be the names of nodes to 
+be placed into power savings mode (using SLURM's hostlist 
+expression format).</li>
+<li><b>ResumeProgram</b>:
+Program to be executed to remove nodes from power saving mode.
+The program executes as <i>SlurmUser</i> (as configured in
+<i>slurm.conf</i>. 
+The argument to the program will be the names of nodes to 
+be removed from power savings mode (using SLURM's hostlist 
+expression format).</li>
+<li><b>ExcludeSuspendNodes</b>:
+List of nodes to never place in power saving mode. 
+Use SLURM's hostlist expression format.
+By default, no nodes are excluded.</li>
+<li><b>ExcludeSuspendPartitions</b>:
+List of partitions with nodes to never place in power saving mode. 
+Multiple partitions may be specified using a comma separator.
+By default, no nodes are excluded.</li>
+</ul></p>
+
+<p>While <i>SuspendProgram</i> and <i>ResumeProgram</i> execute as 
+<i>SlurmUser</i>. The program can take advantage of this to execute 
+programs directly on the nodes as user <i>root</i> through the 
+SLURM infrastructure.
+Example scripts are shown below:
+<pre>
+#!/bin/bash
+# Example SuspendProgram for cluster where every node has two CPUs
+srun --uid=0 --no-allocate --nodelist=$1 echo powersave >/sys/devices/system/cpu0/cpufreq
+srun --uid=0 --no-allocate --nodelist=$1 echo powersave >/sys/devices/system/cpu1/cpufreq
+
+#!/bin/bash
+# Example ResumeProgram for cluster where every node has two CPUs
+srun --uid=0 --no-allocate --nodelist=$1 echo performance >/sys/devices/system/cpu0/cpufreq
+srun --uid=0 --no-allocate --nodelist=$1 echo performance >/sys/devices/system/cpu1/cpufreq
+</pre>
+
+<p>The srun --no-allocate option permits SlurmUser and user root only to spawn 
+tasks directly on the compute nodes without actually creating a SLURM job. 
+No other users have this permission (their requests will generate an invalid 
+credential error message and the event will be logged).
+The srun --uid option permits SlurmUser and user root only to execute a job 
+as some other user. 
+Then SlurmUser uses the srun --uid option, the srun command will try to set 
+its user ID to that value in order to fully operate as the specified user.
+This will fail and srun will report an error to that effect. 
+This does not prevent the spawned programs from running as user root.
+No other users have this permission (their requests will generate an invalid 
+user id error message and the event will be logged).</p>
+
+<p>The slurmctld daemon will periodically (every 10 minutes) log how many 
+nodes are in power save mode using messages of this sort:
+<pre>
+[May 02 15:31:25] Power save mode 0 nodes
+...
+[May 02 15:41:26] Power save mode 10 nodes
+...
+[May 02 15:51:28] Power save mode 22 nodes
+</pre>
+<p>Using these logs you can easily see the effect of SLURM's power saving support.
+You can also configure SLURM without SuspendProgram or ResumeProgram values
+to assess the potential impact of power saving mode before enabling it.</p>
+
+<p style="text-align:center;">Last modified 9 May 2007</p>
+
+<!--#include virtual="footer.txt"-->

doc/html/team.shtml

@@ -45,11 +45,12 @@ Networking, Italy)</li>
 <li>Ashley Pittman (Quadrics)</li>
 <li>Andy Riebs (HP)</li>
 <li>Jeff Squyres (LAM MPI)</li>
+<li>Prashanth Tamraparni (HP, India)</li>
 <li>Kevin Tew (LLNL/Bringham Young University)</li>
 <li>Jay Windley (Linux NetworX)</li>
 <li>Anne-Marie Wunderlin (Bull)</li>
 </ul>
 
-<p style="text-align:center;">Last modified 14 March 2007</p>
+<p style="text-align:center;">Last modified 9 May 2007</p>
 
 <!--#include virtual="footer.txt"-->